Synthesis of Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Nano-Sized Powders by Low Temperature Combustion

The homogeneously dispersed, less agglomerated (Nd0.01Y0.99)3Al5O12 nano-sized powders were synthesized by the low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by the chemical precipitation method. The powders were characterized by TG-DTA, XRD, FT-IR, TEM respectively and the photoluminescence (PL) spectra of (Nd0.01Y0.99)3Al5O12 green and sintered ceramic disks were measured. The results show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by the LCS is in a range of 20～50 nm depending on the thermal treatment temperatures. The effectively induced cross section (σin) with the value 4.03×10-19 cm2 of (Nd0.01Y0.99)3Al5O12 ceramics is about 44% higher than that of single crystal.

Yttrium aluminum garnet (Y_3A_(l5)O_(12)) nanopowders synthesized by the chemical method

The homogeneously dispersed, less agglomerated YAG nanopowders are synthesized by the citrate-gel method followed by low-temperature self-propagating combustion reaction, using Y2O3, Al(NO3)3?9H2O and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and the hard ag-glomerates brought by the chemical precipitation method. The powders are characterized by TG-DTA, XRD, FT-IR and TEM respectively. The experiments show that the forming temperature of YAG crystal phase is 850°C and the pseudo-YAG crystalline appears during the calcination and transforms to pure YAG at 1050°C. The powders with sizes less than 50 nm are observed by TEM micrography, which is consistent with the result calculated by Scherrer's formula. The powders consist of single grains.

Preparation of neodymium-doped yttrium aluminum garnet powders and fibers

Using nitrate precursors, a novel spray-drying assisted citrate gel process for the preparation of neodymium-doped yttrium alumi- num garnet （YAG） phase was developed. Synthesis of single-phase polycrystalline YAG was achieved at temperatures as low as 800 ℃ using the spray-drying methodology whilst conventional approaches currently available require 1000 ℃. Initially, a solution was prepared by mixing aluminum and yttrium nitrates, citric acid, etilenglycol and neodymium oxide. This solution was dried by pulverization （spray dryer） to obtain aggregated precursor powders of the compound. These aggregates were calcined at 800, 850 and 900 ℃ to determine the phase evolution from amorphous to crystalline by X-ray diffraction （XRD）. The morphology of aggregates was characterized by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. Moreover, through XRD it was determined that the crystallization of YAG phase started at about 800 ℃ without any intermediate phases. The powders were composed of spherical aggregates with an average diameter of 1 um. From these powders, ceramic fibers with additions of 2at.% and 5at.% Nd, were extracted from the melt with diameters ranging from 30 um to 50 um.

Preparation of Neodymium-Doped Yttrium Aluminum Garnet Transparent Ceramics by Homogeneous Precipitation Method

substitutes tion, high loosely dis Neodymium doped-yttrium aluminum garnet （Nd ： YAG） transparent polycrystalline ceramics already become of single crystals because they are provided with easy fabrication, low cost, large size, highly doped concentraheat conductivity, mass fabrication, multi-layers and multi-filnctions. The Nd：YAG precursor powders with persed , slightly agglomerated, super fine and YAG cubic crystal phase were synthesized at 1100 ℃ by the homogeneous precipitation method, using Nd2O3, Y2O3, Al（NO3）3·9H2O and urea as raw materials, （NH4）2SO4 as electrical stabilizer, TEOS as sintering additive. The Nd：YAG transparent ceramics were prepared after being vacuum sintered at 1700 ℃ for 5 h. The Nd：YAG ceramic materials were characterized by the TG-DTA, XRD, FT-IR, TEM, FEG-ESEM and FT-PL. The results show that the crystallization temperature of YAG is 850 ℃ and the intermediate crystal phase YAP forming during the heat treatment transforms to YAG cubic crystal phase at 1050 ℃. The lasing wavelength of （Nd0.01 Y0.99）3Al5O12 transparent ceramics is 1.065 μm and there exists a slight red-shift compared to the single crystal with the same chemical composition. The optical transmittance is 45 % in the visible light and 58 % in the near infrared light and the optical transmittance descends with the decreasing the wavelength.

Nanostructured yttrium aluminum garnet powders synthesized by co-precipitation method using tetraethylenepentamine

Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray ...

Application of Stereology on Neodymium-Doped Yttrium Aluminum Garnet (Nd∶YAG) Transparent Ceramics

Nd ： YAG precursor powders were synthesized by homogeneous precipitation, and Nd ： YAG transparent ceramics were prepared by vacuum sintering at 1700 ℃ for 5 h. The ceramic materials were characterized by light transmittance and field emission gun-environment scanning microscope. Using statistics and stereology theory, study was carried out on the quantitative relationships between light transmittance and stereological parameters in three-dimensional Euclidean space. It is found that the transmittance of Nd：YAG with 1 mm in thickness is about 45% and 58% in visible and near-infrared wavelength, respectively. The transmittance linearly increases with increasing equivalent sphere diameter and reaches the theoretical value of single crystal when the equivalent sphere diameter is 20μm. The transmittance decreases with the increasing of mean specific area per unit volume of grain and discrete grains, and the transmittance decreases with increasing mean free distance of grains in Nd：YAG ceramics.

Surgical resection of a large hypopharyngeal hemangioma in an adult using neodymium-doped yttrium aluminum garnet laser: A case report

BACKGROUND Generally,hemangiomas do not require surgical intervention;however,cases of large hemangiomas,potentially involving the throat and trachea,necessitate surgical therapy.Here,we present a case of hypopharyngeal hemangioma in an adult that was successfully treated with neodymium-doped yttrium aluminum garnet(Nd-YAG)laser.CASE SUMMARY Laryngoscopic examination of a 61-year-old man demonstrated the presence of a large,submucosal vascular lesion that extended into the epiglottis,left arytenoid cartilage,lateral to the aryepiglottic fold,and pyriform sinus.The lesion was resected and photocoagulated with limited hemorrhage using Nd:YAG laser.The hypopharyngeal hemangioma was completely excised.The patient showed no recurrence of hypopharyngeal hemangioma during the 1.5-year follow-up period.CONCLUSION Laser therapy is one of the effective tools for treating hemangiomas with rapid,uncontrolled growth or in functional areas,with few side effects and complications.The present case of a male patient with a large hypopharyngeal hemangioma,treated with YAG laser,demonstrates the efficacy of laser photocoagulation in treating cases of hemangiomas,without the risk of bleeding or airway obstruction.The favorable postoperative outcomes demonstrated by our patient with Nd:YAG laser therapy indicate its consideration in the therapy of similar cases.

Neodymium-doped Yttrium Aluminum Garnet Transparent Laser Ceramics Prepared by Co-precipitation Method

Transparent polycrystaUine neodymiumdoped yttrium aluminum garnet ceramics （Nd：YAG） with better chemical stability, excellent optical and high temperature mechanical property is becoming a new laser host material. The Nd：YAG precursor powders with loosely dispersed, slightly agglomerated and YAG cubic crystal phase were synthesized at 1100 ℃ by the co-precipitation method combined with the reverse strike,

Erbium-doped yttrium aluminum garnet laser and advanced plateletrich fibrin+in periodontal diseases:Two case reports and review of the literature

BACKGROUND The goal of periodontal disease treatment is to completely remove bacteria and promote wound healing.The erbium-doped yttrium aluminum garnet(Er:YAG)laser is commonly used to treat periodontal disease.Advanced platelet-rich fibrin+(A-PRF+)secrets growth factors that accelerates soft-and hard-tissue regeneration and wound healing.Herein I present 2 cases of patients with oral diseases treated with a combination of Er:YAG laser and A-PRF+.CASE SUMMARY Case 1 was a female with pocket depth bone loss over 8 mm and infection of tooth 31 and 41,and severe advanced periodontitis with grade III mobility.Case 2 was a male with tooth 22 root end apical swelling and infection and alveolar bony defects.Clinical outcomes were recorded at 6 and 36 mo.In case 1,the Er:YAG laser was used to perform open flap debridement(100 mJ/pulse,15 Hz)and remove calculus and granulation tissue(50 mJ/pulse,30 Hz).In case 2 the laser was used to create a semilunar full thickness flap incision(80 mJ/pulse,20 Hz)and eliminate the pathogen(100 mJ/pulse,15 Hz).In both patients,A-PRF+mixed with bone was used to fill bone defects,and A-PRF+autologous membranes were used to cover tension-free primary flaps.There was no recurrent infection at 36 mo,and tissue regeneration and would healing occurred.CONCLUSION Debridement with an Er:YAG laser followed by treatment with A-PRF+is effective for the treatment periodontal diseases with bone defects.

Synthesis of Ce-doped yttrium aluminum garnet phosphor by impinging streams co-precipitation

Phosphor yttrium aluminum garnet Y3Al5O12 (YAG), activated with trivalent cerium (Ce3+), was synthesized by T-tube impinging streams, T-type vortex impinging streams co-precipitation method (IS-CP) and direct co-precipitation method (D-CP), respectively. The crystallization, morphologies, particle size and particle size distribution of the phosphors obtained under different experimental conditions were studied. The influence of various factors on the luminescence intensity of the phosphor was also investigated, such as feeding methods, volume flow rate, contents of Ce and initial reactant concentration. The results show that the precursors synthesized by T-tube impinging streams co-precipitation reaction transform to Y3Al5O12 (YAG) phosphor at about 1 000 °C. The particles are far smaller and narrower than those prepared by D-CP. In the impinging streams co-precipitation system, the luminescent intensity of YAG?Ce phosphor increases with the increase of liquid flow rate. The intensity firstly increases then decreases with the increasing Ce3+ doping content, and the maximum intensity is shown at 1.67% (molar fraction) Ce. Luminescent intensity gradually decreases with the increase of initial concentration of reactants. At the same operational condition, the luminescent intensity of the phosphors prepared by T-tube impinging streams reactor is higher than that by D-CP, and the luminescent intensity of the phosphors prepared by T-type vortex impinging streams is higher than that by T-tube impinging streams reactor.

Application of Fractals on Microstructure of Neodymium-Doped Yttrium Aluminum (Nd∶YAG) Transparent Ceramics

Nd∶YAG precursor powders were synthesized by homogeneous precipitation and Nd∶YAG transparent ceramics were prepared by vacuum sintering at 1700 ℃ for 5 h. The ceramic materials were characterized by light transmittance, field emission gun-environment scanning microscope. Fractal geometry was used to study the quantitative relationships between light transmittance and fractal dimensions of Nd∶YAG transparent ceramics. It was found that the transmittance of Nd∶YAG with 1 mm in thickness was about 45% and 58% in visible and near-infrared region respectively. The microstructures of Nd∶YAG transparent ceramics were obvious fractal characteristic and fractal dimensions depart a little from two-dimension. The light transmittance decreased with increasing of fractal dimension and nonlinear fit curve was y=1350-1185x+269x2 between fractal dimension and light transmittance of Nd∶YAG transparent ceramics.

Er:YAG激光和传统车针去龋后牙本质粘接强度的比较

目的:比较使用不同模式Er:YAG激光以及传统车针去龋后牙本质与复合树脂的粘接强度。方法:选用人类离体磨牙模拟龋坏,分别采用Er:YAG激光中短脉冲(medium short pulse,MSP)模式、Er:YAG激光超短脉冲(super short pulse,SSP)模式和传统车针去除模拟的龋坏后,采用自酸蚀粘接剂将牙体标本与复合树脂粘接制成试件。使用万能试验机对试件进行拉伸试验,测得断裂负荷和粘接强度,并采用单因素方差分析和Tukey多重比较进行统计学分析。采用扫描电子显微镜观察3种不同去龋方式处理后的牙本质表面形态,以及涂布自酸蚀粘接剂并固化后试件的横截面形态。结果:使用Er:YAG激光MSP模式处理后牙本质与复合树脂的粘接强度最高,SSP模式处理后次之,传统车针处理后最低,但差异无统计学意义(P>0.05)。扫描电子显微镜图像显示,Er:YAG激光MSP模式处理后的牙本质表面较平坦,牙本质小管内几乎没有残屑;Er:YAG激光SSP模式处理后的牙本质表面呈现鳞片状,牙本质小管内可见少量碎屑;而传统车针处理后牙本质小管大部分处于被表面牙本质部分甚至完全遮盖的状态,牙本质小管内充满残屑。结论:使用Er:YAG激光去龋相比传统车针去龋可以获得较好的牙本质粘接强度,且对牙本质小管的处理深度和洁净度明显优于传统车针去龋,其中MSP模式更佳。

Fabrication of YAG:Ce^(3+) and YAG:Ce^(3+),Sc^(3+) Phosphors by Spark Plasma Sintering Technique

In this study,a single-doped phosphors yttrium aluminum garnet(Y_(3)Al_(5)O_(12),YAG):Ce^(3+),single-doped YAG:Sc^(3+),and double-doped phosphors YAG:Ce^(3+),Sc^(3+) were prepared by spark plasma sintering(SPS)(lower than 1 200℃).The characteristics of synthesized phosphors were determined using scanning electron microscopy(SEM),X-ray diffraction(XRD),and fluorescence spectroscopy.During SPS,the lattice structure of YAG was maintained by the added Ce^(3+) and Sc^(3+).The emission wavelength of YAG:Ce^(3+) prepared from SPS(425-700 nm) was wider compared to that of YAG:Ce^(3+) prepared from high-temperature solid-state reaction(HSSR)(500-700 nm).The incorporation of low-dose Sc^(3+) in YAG:Ce^(3+) moved the emission peak towards the short wavelength.

Nd:YAG激光爆破模式对后囊膜切开术效果的影响

目的探讨掺钕钇铝石榴石(Nd:YAG)激光不同爆破模式对后囊膜切开术效果的影响。方法收集2017年12月至2019年12月承德医学院附属医院治疗的后囊膜混浊患者59例59眼,采用随机数字表法将其分为单脉冲组(29例)和多脉冲组(30例)。比较两组手术前后最佳矫正视力(BCVA)、眼压、前房闪辉和前房细胞发生等级、黄斑中心区视网膜厚度和生活质量等。结果术后1周,两组BCVA均高于术前(P<0.05)。两组不同时间点眼压比较,差异有统计学意义(P<0.05)。术后1周,两组前房闪辉和前房细胞发生等级均低于术后1 h(P<0.05)。单脉冲组Nd:YAG激光总能量低于多脉冲组(P<0.05)。两组不同时间点黄斑中心区视网膜厚度比较,差异有统计学意义(P<0.05)。结论后囊膜切开术中Nd:YAG激光单脉冲模式较多脉冲模式节省激光能量,减轻眼内光损伤,临床中可首选应用。

稀土氧化物掺杂对Y_(3)Al_(5)O_(12)热障涂层材料热膨胀性能的影响

采用固相烧结法制备稀土氧化物(Gd_(2)O_(3),Er_(2)O_(3),Sc_(2)O_(3))掺杂钇铝石榴石(YAG)热障涂层材料.通过X射线衍射仪、扫描电镜和热膨胀仪研究掺杂离子种类、含量和掺杂位置对材料物相组成、微观形貌和热膨胀性能的影响规律.结果显示:阳离子半径小于Y^(3+)的Sc_(2)O_(3)掺杂YAG陶瓷材料热膨胀性能最优.当掺杂量x为0.6时,(Y_(0.4)Sc_(0.6))_(3)Al_(5)O_(12)陶瓷的平均热膨胀系数最大,约为12.34×10^(-6)K^(-1),比纯YAG陶瓷的平均热膨胀系数(~8×10^(-6)K^(-1))提高了约50%.

掺钕钇铝石榴石激光联合脱敏牙膏封闭牙本质小管后抗酸蚀的效果评价

目的 评估掺钕钇铝石榴石(Nd∶YAG)激光和含有氟化亚锡系统的脱敏牙膏不同应用顺序对牙本质小管封闭效果的影响。方法 选择12颗完整的新鲜拔除的人第三磨牙制备成0.8 mm厚牙本质片,将每个牙本质片再分为4小片,取其中3小片,用6%的柠檬酸进行腐蚀,随机分配至以下3组(n=12):(1)对照组:无处理;(2)Nd∶YAG激光+牙膏(TB)组:先用Nd∶YAG激光照射,后用脱敏牙膏刷牙;(3)TB+Nd∶YAG组:先用脱敏牙膏刷牙,后用Nd∶YAG激光照射。Nd∶YAG激光照射参数均为:1 W,15脉冲/s,脉冲宽度150μs,照射10 s, 6个循环。经上述处理后,将Nd∶YAG+TB组和TB+Nd∶YAG组的12个牙本质片随机分配到4个亚组(n=3),分别在可口可乐液中接受酸蚀0、5、10、15 min。采用扫描电子显微镜观察各组牙本质片并拍片,由8名单盲检查员根据统一标准给出评分,采用方差分析对各组评分进行比较。结果 酸蚀前,Nd∶YAG+TB组和TB+Nd∶YAG组的牙本质小管封闭评分分别为(4.83±0.09)分和(3.85±0.66)分,均明显高于对照组的(0.10±0.07)分(P均<0.0001),Nd∶YAG+TB组与TB+Nd∶YAG组差异无统计学意义(P=0.0590)。Nd∶YAG+TB组酸蚀5、10、15 min牙本质小管封闭评分分别为(4.33±0.60)、(4.27±0.24)、(3.63±0.07)分,与TB+Nd∶YAG组的(4.04±0.10)、(3.76±0.59)、(3.17±0.29)分差异均无统计学意义(P均>0.05)。在Nd∶YAG+TB亚组中,酸蚀15 min牙本质小管封闭评分明显低于酸蚀前(P=0.0011)。在TB+Nd∶YAG组中,酸蚀前后牙本质小管封闭评分间差异无统计学意义(P>0.05)。结论 适当参数的Nd∶YAG激光照射结合使用脱敏牙膏,不论先后顺序,均可以产生良好的牙本质小管封闭效果,但是先用脱敏牙膏刷牙后用Nd∶YAG激光照射组在酸蚀后的牙本质封闭效果更稳定。

Nd:YAG激光治疗糖尿病患者后发性白内障的临床研究

目的 探讨掺钕钇铝石榴石(Nd:YAG)激光后囊膜切开术治疗伴有2型糖尿病(T_(2)DM)的后发性白内障的疗效及安全性。方法 对2019年12月-2021年9月江西省景德镇市第一人民医院收治的60例行Nd:YAG激光后囊膜切开术的后发性白内障患者临床资料进行回顾性分析,其中伴T_(2)DM患者30例(观察组),非T_(2)DM患者30例(对照组)。比较2组术前、术后4周视力、眼压、前房深度及角膜内皮细胞变化情况,记录并发症。结果 术后4周,2组裸眼视力、矫正视力较术前明显提高,而眼压、前房深度、角膜内皮细胞密度(CECD)、角膜内皮细胞变异系数及六边形细胞比例较术前明显降低(P<0.05),但组间差异不明显(P>0.05);观察组术后总并发症发生率为36.67%,较对照组的23.33%略高,但差异无统计学意义(P>0.05)。结论 采用Nd:YAG激光后囊膜切开术治疗伴有T_(2)DM的后发性白内障安全有效,与非T_(2)DM患者疗效相当。

Fabrication and long persistent luminescence of Ce3+-Cr3+co-doped yttrium aluminum gallium garnet transparent ceramics

Pe rsistent luminescence(Pers L)materials are widely used in safety indication,traffic and transportation signs,architectural decoration and other fields.In this paper,(Y_(1-x)Ce_(x))(Al_(0.9995)Cr_(0.0005))_(2)Ga_(3)O_(12)(x=0.001,0.002,0.003,0.005)transparent ceramics were successfully prepared by solid-state reaction method in air followed by HIP post-treatment.With the increase of Cedoping concentration,the optical quality of the as-prepared ceramics is improved and the morphology is denser.Luminescent quenching occurs when the Ceconcentration is more than 0.2%.The as-prepared transparent ceramics we re annealed in different atmosphere s.From the PersL decay curve s,the transparent ce ramics after air annealing show the best PersL performance:luminance with 4424.0 mcd/m^(2)and PersL duration over865 min after ceasing 365 nm excitation,respectively.The effects of Cedoping concentration and annealing atmospheres are also discussed in detail.

Finite element analysis of neodymium： yttrium-aluminum-garnet incisions for the prevention of anterior capsule contraction syndrome

Background Anterior capsular contraction syndrome is a potential complication of continuous curvilinear capsulorhexis （CCC）. Three neodymium： yttrium-aluminum-garnet （Nd：YAG） laser relaxing incisions decrease anterior capsular contraction but the mechanism is unknown. The present study analyzed the biomechanical mechanism of three Nd：YAG laser relaxing incisions made to reduce anterior capsular contraction. Methods A three-dimensional control model and a three-dimensional Nd：YAG model of the anterior capsule with an opening diameter of 6 mm were created. Three incisions of 1 mm in length were made centrifugally at intervals of 120~ around the opening circle. The stress alterations of the anterior capsule after CCC with and without Nd：YAG relaxation were numerically simulated and compared. Results In the control model, the stress was axially uniform in the inner area and relatively high near the inner rim of the opening. Meanwhile, in the Nd：YAG model, the stress level was very low in the inner opening areas, especially near the three incisions. The relaxing incisions in the Nd：YAG model significantly released the relatively high stress on the anterior capsule. Additionally, there was a high stress gradient near the relaxing incisions. Conclusion Biomechanical effects of stress release may be the preventive mechanism of Nd：YAG incision against anterior capsular contraction syndrome.

掺钕钇铝石榴石激光辅助牙周基础治疗Ⅲ期牙周炎的临床疗效

目的探讨掺钕钇铝石榴石(Nd:YAG)激光辅助牙周基础治疗Ⅲ期牙周炎的临床疗效。方法选取2020年8月至2021年9月苏州口腔医院牙周科收治的44例Ⅲ期牙周炎患者作为研究对象,按照掷硬币法分为对照组与观察组,每组22例。对照组采用龈下刮治和根面平整(SRP)单独治疗,观察组采用SRP联合Nd:YAG治疗,比较两组不同时间出血指数(BI)、牙周探诊深度(PD)和临床附着丧失(CAL)。结果治疗后1、3个月,两组BI、PD、CAL值均低于前一时间点,且观察组BI、PD值均低于对照组,观察组治疗后1个月CAL值低于对照组,差异有统计学意义(P<0.05),两组治疗后3个月CAL值比较差异无统计学意义。结论Nd:YAG激光辅助牙周基础治疗可降低Ⅲ期牙周炎BI值,改善PD深度,但对CAL的改善无明显优势。